/*****************************************************************************

gifhisto - make a color histogram from image color frequencies

*****************************************************************************/
// SPDX-License-Identifier: MIT
// SPDX-File-Copyright-Txt: (C) Copyright 1989 Gershon Elber

#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "getarg.h"
#include "gif_lib.h"

#define PROGRAM_NAME "gifhisto"

#define DEFAULT_HISTO_WIDTH 100 /* Histogram image diemnsions. */
#define DEFAULT_HISTO_HEIGHT 256
#define HISTO_BITS_PER_PIXEL 2 /* Size of bitmap for histogram GIF. */

static char *VerStr = PROGRAM_NAME VERSION_COOKIE __DATE__ ", " __TIME__ "\n";
static char *CtrlStr = PROGRAM_NAME
    " v%- t%- s%-Width|Height!d!d n%-ImageNumber!d b%- h%- GifFile!*s";

static int ImageWidth = DEFAULT_HISTO_WIDTH, ImageHeight = DEFAULT_HISTO_HEIGHT,
           ImageN = 1;
static GifColorType HistoColorMap[] = {/* Constant bit map for histograms: */
                                       {0, 0, 0},
                                       {255, 0, 0},
                                       {0, 255, 0},
                                       {0, 0, 255}};

static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut);

/******************************************************************************
 Interpret the command line and scan the given GIF file.
******************************************************************************/
int main(int argc, char **argv) {
	int i, j, ErrorCode, NumFiles, ExtCode, CodeSize, NumColors = 2,
	                                                  ImageNum = 0;
	bool Error, TextFlag = false, SizeFlag = false, ImageNFlag = false,
	            BackGroundFlag = false, HelpFlag = false, GifNoisyPrint;
	long Histogram[256];
	GifRecordType RecordType;
	GifByteType *Extension, *CodeBlock;
	char **FileName = NULL;
	GifRowType Line;
	GifFileType *GifFileIn = NULL, *GifFileOut = NULL;

	/* Same image dimension vars for both Image & ImageN as only one allowed
	 */
	if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifNoisyPrint, &TextFlag,
	                       &SizeFlag, &ImageWidth, &ImageHeight,
	                       &ImageNFlag, &ImageN, &BackGroundFlag, &HelpFlag,
	                       &NumFiles, &FileName)) != false ||
	    (NumFiles > 1 && !HelpFlag)) {
		if (Error) {
			GAPrintErrMsg(Error);
		} else if (NumFiles > 1) {
			GIF_MESSAGE("Error in command line parsing - one GIF "
			            "file please.");
		}
		GAPrintHowTo(CtrlStr);
		exit(EXIT_FAILURE);
	}

	if (HelpFlag) {
		(void)fprintf(stderr, VerStr, GIFLIB_MAJOR, GIFLIB_MINOR);
		GAPrintHowTo(CtrlStr);
		exit(EXIT_SUCCESS);
	}

	if (NumFiles == 1) {
		if ((GifFileIn = DGifOpenFileName(*FileName, &ErrorCode)) ==
		    NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	} else {
		/* Use stdin instead: */
		if ((GifFileIn = DGifOpenFileHandle(0, &ErrorCode)) == NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	}

	for (i = 0; i < 256; i++) {
		Histogram[i] = 0; /* Reset counters. */
	}
	/* Scan the content of the GIF file and load the image(s) in: */
	do {
		if (DGifGetRecordType(GifFileIn, &RecordType) == GIF_ERROR) {
			QuitGifError(GifFileIn, GifFileOut);
		}

		switch (RecordType) {
		case IMAGE_DESC_RECORD_TYPE:
			if (DGifGetImageDesc(GifFileIn) == GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}

			if (GifFileIn->Image.ColorMap) {
				NumColors =
				    GifFileIn->Image.ColorMap->ColorCount;
			} else if (GifFileIn->SColorMap) {
				NumColors = GifFileIn->SColorMap->ColorCount;
			} else {
				GIF_EXIT("Neither Screen nor Image color map "
				         "exists.");
			}

			if ((ImageHeight / NumColors) * NumColors !=
			    ImageHeight) {
				GIF_EXIT("Image height specified not dividable "
				         "by #colors.");
			}

			if (++ImageNum == ImageN) {
				/* This is the image we should make histogram
				 * for:       */
				Line =
				    (GifRowType)malloc(GifFileIn->Image.Width *
				                       sizeof(GifPixelType));
				GifQprintf(
				    "\n%s: Image %d at (%d, %d) [%dx%d]:     ",
				    PROGRAM_NAME, ImageNum,
				    GifFileIn->Image.Left, GifFileIn->Image.Top,
				    GifFileIn->Image.Width,
				    GifFileIn->Image.Height);

				for (i = 0; i < GifFileIn->Image.Height; i++) {
					if (DGifGetLine(
					        GifFileIn, Line,
					        GifFileIn->Image.Width) ==
					    GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}
					for (j = 0; j < GifFileIn->Image.Width;
					     j++) {
						Histogram[Line[j]]++;
					}
					GifQprintf("\b\b\b\b%-4d", i);
				}

				free((char *)Line);
			} else {
				/* Skip the image: */
				/* Now read image itself in decoded form as we
				 * dont      */
				/* really care what is there, and this is much
				 * faster.   */
				if (DGifGetCode(GifFileIn, &CodeSize,
				                &CodeBlock) == GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
				while (CodeBlock != NULL) {
					if (DGifGetCodeNext(GifFileIn,
					                    &CodeBlock) ==
					    GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}
				}
			}
			break;
		case EXTENSION_RECORD_TYPE:
			/* Skip any extension blocks in file: */
			if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) ==
			    GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}

			while (Extension != NULL) {
				if (DGifGetExtensionNext(
				        GifFileIn, &Extension) == GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
			}
			break;
		case TERMINATE_RECORD_TYPE:
			break;
		default: /* Should be trapped by DGifGetRecordType. */
			break;
		}
	} while (RecordType != TERMINATE_RECORD_TYPE);

	/* We requested suppression of the background count: */
	if (BackGroundFlag) {
		Histogram[GifFileIn->SBackGroundColor] = 0;
	}

	if (DGifCloseFile(GifFileIn, &ErrorCode) == GIF_ERROR) {
		PrintGifError(ErrorCode);
		exit(EXIT_FAILURE);
	}

	/* We may required to dump out the histogram as text file: */
	if (TextFlag) {
		for (i = 0; i < NumColors; i++) {
			printf("%12ld  %3d\n", Histogram[i], i);
		}
	} else {
		int Color, Count;
		long Scaler;
		/* Open stdout for the histogram output file: */
		if ((GifFileOut = EGifOpenFileHandle(1, &ErrorCode)) == NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}

		/* Dump out screen descriptor to fit histogram dimensions: */
		if (EGifPutScreenDesc(GifFileOut, ImageWidth, ImageHeight,
		                      HISTO_BITS_PER_PIXEL, 0,
		                      GifMakeMapObject(4, HistoColorMap)) ==
		    GIF_ERROR) {
			QuitGifError(GifFileIn, GifFileOut);
		}

		/* Dump out image descriptor to fit histogram dimensions: */
		if (EGifPutImageDesc(GifFileOut, 0, 0, ImageWidth, ImageHeight,
		                     false, NULL) == GIF_ERROR) {
			QuitGifError(GifFileIn, GifFileOut);
		}

		/* Prepare scan line for histogram file, and find scaler to
		 * scale    */
		/* histogram to be between 0 and ImageWidth: */
		Line = (GifRowType)malloc(ImageWidth * sizeof(GifPixelType));
		for (Scaler = 0, i = 0; i < NumColors; i++) {
			if (Histogram[i] > Scaler) {
				Scaler = Histogram[i];
			}
		}
		Scaler /= ImageWidth;
		if (Scaler == 0) {
			Scaler = 1; /* In case maximum is less than width. */
		}
		/* Dump out the image itself: */
		for (Count = ImageHeight, i = 0, Color = 1; i < NumColors;
		     i++) {
			int Size;
			if ((Size = Histogram[i] / Scaler) > ImageWidth) {
				Size = ImageWidth;
			}
			for (j = 0; j < Size; j++) {
				Line[j] = Color;
			}
			for (j = Size; j < ImageWidth; j++) {
				Line[j] = GifFileOut->SBackGroundColor;
			}

			/* Move to next color: */
			if (++Color >= (1 << HISTO_BITS_PER_PIXEL)) {
				Color = 1;
			}

			/* Dump this histogram entry as many times as required:
			 */
			for (j = 0; j < ImageHeight / NumColors; j++) {
				if (EGifPutLine(GifFileOut, Line, ImageWidth) ==
				    GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
				GifQprintf("\b\b\b\b%-4d", Count--);
			}
		}

		if (EGifCloseFile(GifFileOut, &ErrorCode) == GIF_ERROR) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	}

	return 0;
}

/******************************************************************************
 Close both input and output file (if open), and exit.
******************************************************************************/
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut) {
	if (GifFileIn != NULL) {
		PrintGifError(GifFileIn->Error);
		EGifCloseFile(GifFileIn, NULL);
	}
	if (GifFileOut != NULL) {
		PrintGifError(GifFileOut->Error);
		EGifCloseFile(GifFileOut, NULL);
	}
	exit(EXIT_FAILURE);
}

/* end */
